Category: Cardiology

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Case: Andrew is a 16yo post-pubertal male without any past medical history who comes to clinic for his annual well-child check. His vitals at triage showed a blood pressure of 142/92. You note that he was seen in urgent care twice in the last 2 months with a similarly high blood pressures. His BMI is >95th percentile. How should you address his blood pressure today? Specifically, what further workup and/or treatment should be undertaken?

Diagnosis

How is high blood pressure classified? (based on The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents)

Hypertension is defined as an average systolic blood pressure (SBP) and/or diastolic BP (DBP) that is ≥95th percentile for gender, age, and height on 3 occasions.

These 3 occasions needs to be separated by days-weeks

Note: Measures obtained by oscillometric devices (aka automatic BP machines) that exceed the 90th percentile should be repeated by auscultation.

Prehypertension in children is defined as average SBP or DBP levels that are ≥90th percentile but <95th percentile.

As with adults, adolescents with BP levels >120/80 mmHg should be considered prehypertensive.

A patient with BP levels ≥95th percentile in a physician’s office or clinic, who is normotensive outside a clinical setting, has “white-coat hypertension.”

Ambulatory BP monitoring (ABPM) is usually required to make this diagnosis.

Image Credit: Pixabay

Epidemiology

The prevalence of primary and secondary hypertension is 4.5% and 13%, respectively (Gupta-Malhotra et al, 2015)

Given low screening rates, true prevalence may be higher

Children with essential (primary) hypertension tend to be older (>6), have a family history of hypertension (Gupta-Malhotra et al, 2015)

Conversely, infants and preschool-aged children with elevated blood pressure are more likely to have a secondary form of hypertension.

Etiology & Workup

While secondary causes of hypertension are more common in children than adults, children can also have primary hypertension (see Table below

<1yr old (%)

1-5 years (%)

6-12 years (%)

13-19years (%)

Respiratory (61)

Respiratory (29)

Essential (57)

Essential (49)

Renal (13)

Renal (27)

Renal (27)

Renal (20)

Medication Related (9)

Essential (19)

Neurological (7)

Medication Related (11)

Table 1: Most common causes of hypertension by age (adapted fromGupta-Malhotra et al, 2015)

Workup for secondary causes should be individualized

Children with BPs ≥95th percentile (stage 1 hypertension) should have the following (NHBPEP, 2004; Ingelfinger JR, 2014):

Back to the Case: Upon seeing Andrew, you repeat his blood pressure manually, which is also high. He has no other “red flags” on history or exam. Given his age and comorbidities (obesity), Andrew most likely has essential hypertension (3 readings >140/90). Initial workup should include: basic labs (BMP, CBC, and UA) and imaging (renal ultrasound and ECHO). Provided these are all reassuring, he should first undergo lifestyle interventions, with medical management initiated if his BPs do not normalize.

References

“The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents.” Pediatrics Aug 2004, 114 (Supplement 2) 555-576

Following “dropped” beat, there is a diastolic pause, and cycle continues

Characteristically thought of as a “benign rhythm” found in asymptomatic individuals and there is low risk of progressing to third degree heart block. In fact, up to 10% of healthy will episodes of type 1, second degree heart block (Dickinson, 2005).

However, this may be seen in myocarditis, congenital heart disease, and following cardiac surgery

Case:

A 16 year-old male presents to the ED after a syncopal episode. He currently feels well and wants to go home. Below is his EKG, what do you think?

Discussion:

The above presentation (syncopal event) paired with this EKG is concerning for the Brugada syndrome.

Epidemiology:

The Brugada syndrome was first described in 1992 by Drs. Pedro and Josep Brugada in a case report of 8 patient with aborted sudden cardiac death (SCD), though cases of sudden unexplained nocturnal death (SUND) had been described previously in various southeast Asian populations (Juang JM et al, 2004).

Some estimate that 4-12% of SCD can be attributed to the syndrome, with a higher prevalence in SE Asian populations (Gourraud JB et al, 2016)

Median age of presentation is 41, though has be reported in neonates through the elderly.

While many mutations have been described, the Brugada syndrome appears to result from mutations in the Na+ channel, affecting the SCN5A gene (Behere SP et al, 2015)

Note: Only 20% of patients with Brugada syndrome have a documented mutation in the SCN5A gene. Studies show a autosomal dominant transmission with incomplete penetrance (Juang JM et al, 2004).

Clinical Presentation:

In the original description of the syndrome, the Brugada brothers noted that all patients presented with syncope, with 5/7 progressing immediately to cardiac arrest and the other 2 progressing to cardiac arrest over the next 2 weeks

Registry data indicates that almost 1/3 present with syncope, 6% with SCD, though >60% were asymptomatic at the time of diagnosis (Probst V et al, 2010)

Created on 8/4/2016 by Hiral Mehta, MD

CASE:

Griffin is a 5 y/o boy who comes into the ER. Parents state that earlier today he began complaining of his “heart running fast” and his chest hurting. His cardiac exam is unremarkable. You decide to get an EKG as part of your work up.

What should I know when interpreting a pediatric EKG?

EKGs are simple, relatively straightforward to obtain, and provide a great deal of important information- if you are able to interpret them!

First: Lead placement

There are several different types of lead set ups. Intuitively, more leads generally provide more information. Remember, EKGs are vector representations of electrical depolarization. The more “viewpoints” you have, the more information you can gather.

5 Lead-ECG:This is what we generally have on our hospitalized kids who are on CRM (cardio-respiratory monitoring).

12-lead EKG: This is the standard 12 lead EKG that we order. In pediatrics, we use the “V4R lead” to better assess the right ventricular potentials because the RV extends to the right of the sternum in children. This gets confusing- you should still use the leads that the machine labels “V1”-”V6” in that order (R->L anatomically), but start V1 further to the right (and relabel the EKG when it prints out).

How do I interpret this EKG?

Good general guidelines: have a systematic approach. Look at as many EKGs as possible to start getting a sense of what is “normal”, especially at various ages. One standard approach is to think through EKGs as an approach of “rate, rhythm, and axis” but really, everyone tends to develop their own methodology.

It is helpful to think of the EKG as a “graph” of electrical activity on the “Y-axis” and time on the “X-axis.” (For more in depth explanation, please see videos at end of the post).

The standard speed of paper is 25mm/sec, but it is always helpful to make sure EKG strips you are looking at are run at the standard speed

A “small box” is 0.04 seconds on the time axis and 0.1mV on the electrical axis

A “big box” is 0.2 seconds on the time axis and 0.5mV on the electrical axis

Axis: There are multiple ways of determining the “axis.” Below highlights 1 of these methods. “Normal” axis changes with age, with infants having a “rightward” axis. As children grow older, the axis becomes more leftward.

(Note: In case you were wondering, there is an atrial repolarization wave, but it is “hidden” in the QRS complex).

Note: Remember, standard speed of paper is 25mm/sec, therefore, a “small box” is 0.04 seconds on the time axis and 0.1mV on the electrical axis and a “big box” is 0.2 seconds on the time axis and 0.5mV on the electrical axis

PR interval: This reflects conduction from the SA node → AV node.

Normally thought of as 0.12- 0.2 sec (one “big box”) for adults; however in children it varies with age and HR.

QT interval: Represents the time it takes for ventricular depolarization and repolarization. This is one of the intervals that can’t really be obtained just by reading off what the EKG machine calculates, since QT varies with the HR and the individual RR intervals. This will be expanded upon in a future topic, but for now:

The calculated “corrected QT” interval (QTc) is most commonly derived with Bazett’s Formula:

QTc=QT√RR

Use the RR interval preceding the QT interval that you’re looking at. This formula is most accurate for HRs 60-100!

Infants normally have a longer QTc (under 6 months, QTc of <490 msec is considered normal). Children older than 6 months should have a QTc <440msec.

What are you concerned about?

This X-ray demonstrates cardiomegaly with prominent lung markings, which is suggestive of heart failure as the etiology of this infant’s respiratory distress.

Heart Failure in Children: The Basics

In the US, the most common cause of pediatric heart failure is structural congenital heart disease. In children with structurally normal hearts, cardiomyopathy is the most common cause of heart failure. [Hsu et al, 2009]

Heart failure presents when the metabolic demands of the body exceed cardiac output.

As you are starting your morning ED shift, your first patient is a 2-year-old boy, previously healthy, who is coming in with 5 days of fevers at home. Fevers have occurred daily and have been as high as 39.5ºC. His mother states that during this time he has been more fussy than usual and has been not been eating or drinking very well. Vital signs demonstrate a temperature of 38.9ºC, HR of 150, RR is 20. His BP is 110/60. On exam, he is fussy and appears ill. His conjunctiva are injected and you appreciate limbic sparing. Oropharyngeal exam is shown below. You also note a diffuse macular rash. What are you most concerned about?

Kole A, Chandakole D. N Engl J Med 2015;373:467-467.

Answer: The picture above shows a strawberry tongue with fissured lips, which in conjunction with 5 days of fever, rash and bilateral conjunctival injection is concerning for Kawasaki Disease (KD). KD is an acute vasculitis of still unknown etiology affecting primarily infants and children. KD affects coronary arteries, and without IVIG, 20% of children will go on to have coronary artery aneurysms (Newburger et al). Diagnosis of KD is primarily clinical, and requires 5 or more days of fever in conjunction with 4/5 clinical criteria (see below). For those children with persistent fever, but who lack all 4 criteria (child mentioned in case has 3), diagnosis utilizes lab and ECHO findings (listed below). In children with classic Kawasaki, as well as those with incomplete disease, the mainstay of acute management is IVIG paired with high-dose aspirin. For more information, please review the attached references.

Diagnostic Criteria of Kawasaki Disease (requires at least 5 days of fever)

Changes in extremities: Acute: Erythema and edema of hands and feet Convalescent: Desquamation of fingertips

Polymorphous exanthema

Bilateral, painless bulbar conjunctival injection without exudate

Changes in lips and oral cavity: Erythema and cracking of lips, strawberry tongue, diffuse injection of oral and pharyngeal mucosae

Cervical lymphadenopathy (≥1.5 cm in diameter), usually unilateral

Diagnostic Criteria for children who have at least 5 days of fever and only 2-3 findings mentioned above:

Obtain Labs: CRP/ESR, CBC, LFTs, and UA

If CRP < 3 mg/dl AND ESR <40

If fever continues, re-evaluate

If fever defervesces, no follow-up required (EXCEPTION: in children who develop desquamation, an ECHO should be obtained).